> ## Documentation Index
> Fetch the complete documentation index at: https://docs.core3.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Getting started with CORE3 MCP

> Connect Cursor, Claude Desktop, or another MCP client to the public core3 server at https://api.core3.io/v1/mcp—no API key required.

This guide walks you through connecting an MCP client to **`core3`**, the public CORE3 MCP server. Once connected, your agent can call read-only tools for category quality scores, project metrics, Proof of Voice, and exchange risk data.

## Server URL

```text theme={null}
https://api.core3.io/v1/mcp
```

## Transport

CORE3 MCP uses **Streamable HTTP**—a stateless HTTP transport defined by the MCP specification. Your client opens a session against the endpoint URL; no WebSocket or stdio process is required.

## Authentication

No authentication is required. You do **not** need an API key or **`x-api-key`** header to use MCP tools.

<Tip>
  If you need the full REST API surface, search, ratings pagination, or commercial rate limits, request an API key via [CORE3 for partners](/core3-for-partners) or contact **[info@core3.io](mailto:info@core3.io)**.
</Tip>

## Conventions

* **`slug`** — Canonical project or exchange identifier passed to most tools. Brand names often differ from the slug (for example Compound → `compound-governance-token`, Coinbase → `coinbase-exchange`). Prefer **`resolve_project_slug`** when the user gives a brand, ticker, or name. Use **`get_projects_list`** when you need the full project catalog. There is no exchange discovery tool—only call exchange score tools with a confirmed CORE3 slug.
* **`days`** — Positive integer for history tools (`get_project_categories_scores_dynamic`, `get_exchange_categories_scores_dynamic`). Specifies how many days of score history to return.

## Connect your client

### Cursor

Add the server to your MCP configuration file (project-level `.cursor/mcp.json` or user-level settings):

```json cursor-mcp.json theme={null}
{
  "mcpServers": {
    "core3": {
      "url": "https://api.core3.io/v1/mcp"
    }
  }
}
```

Restart Cursor or reload MCP servers after saving the file. The server appears as **core3** in your agent's available tools.

### Claude Desktop

Add the server to `claude_desktop_config.json`:

```json claude_desktop_config.json theme={null}
{
  "mcpServers": {
    "core3": {
      "url": "https://api.core3.io/v1/mcp"
    }
  }
}
```

Restart Claude Desktop for the configuration to take effect.

### Other MCP clients

Any client that supports MCP Streamable HTTP can connect using the same URL. Refer to your client's documentation for the exact configuration format.

## Your first tool calls

After connecting, verify the integration with these tools in order:

### 1. Check health

Call **`check_health`** with no parameters. A successful response confirms the server is reachable:

```text theme={null}
The service is healthy
```

### 2. Resolve a project slug

Call **`resolve_project_slug`** with `query: "ethereum"`. On success, `structuredContent.status` is `resolved` and you get `resolvedSlug` / `resolvedName` for follow-up tools.

If status is `ambiguous` or `not_found`, do not guess a slug or answer for a different entity—ask the user to choose or provide the exact CORE3 slug.

Optionally call **`get_projects_list`** to browse the full catalog (`structuredContent.projects` and `totalProjects`).

### 3. Fetch a category quality score

Call **`get_project_security_score`** with `slug: "ethereum"`. The response includes:

* **`content`** — Human-readable confirmation text for the agent
* **`structuredContent`** — Machine-readable JSON with envelope fields and the score object

Example structured payload shape:

```json theme={null}
{
  "status": "ok",
  "entityType": "project",
  "metric": "security_score",
  "requestedSlug": "ethereum",
  "resolvedSlug": "ethereum",
  "scoreType": "category_quality",
  "scoreDirection": "higher_is_better",
  "interpretationHint": "This is a category quality/calculation score, not overall PoL. Higher scores are better (stronger quality). Lower scores are worse. Never treat a high category score as higher risk.",
  "score": {
    "score": 86.6,
    "rating": "AAA",
    "confidence": "High"
  }
}
```

`rating` is a letter grade (AAA–D). `confidence` is Exceptional, High, Moderate, or Low. See [Tools reference](/mcp-tools-reference) for every tool's return shape.

## Response format

Every tool (except **`check_health`**) returns two layers:

| Field               | Purpose                                                |
| ------------------- | ------------------------------------------------------ |
| `content`           | Text summary the agent reads during conversation       |
| `structuredContent` | JSON payload your integration or agent logic can parse |

Agents typically surface the text summary to users while using `structuredContent` for downstream reasoning or display. Detail and score tools include a shared envelope (`status`, `entityType`, `metric`, slug fields, and—for scores—`scoreType` / `scoreDirection`).

## Troubleshooting

| Issue                                | What to try                                                                                                                                                 |
| ------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Server not appearing in client       | Confirm the URL is exactly `https://api.core3.io/v1/mcp` and restart the client                                                                             |
| Tool returns an error for a slug     | Call **`resolve_project_slug`** first; do not continue after `ambiguous` or `not_found`                                                                     |
| CORS errors in browser-based clients | Use a supported MCP client rather than calling the endpoint directly from a browser                                                                         |
| Need data not exposed as a tool      | Use the [Projects Data API](/projects-data-api) or [Exchanges Data API](/exchanges-data-api)—search, ratings, overall PoL, and other endpoints require REST |

<Tip>Need full REST API access, higher rate limits, or commercial terms? Contact [info@core3.io](mailto:info@core3.io)</Tip>

## Next steps

* Browse the full [Tools reference](/mcp-tools-reference) for all 23 tools, parameters, and REST equivalents.
* Read [MCP overview](/mcp-overview) for scope and limitations.
* Pair category score results with [Project PoL methodology](/project-pol-methodology) or [CEX PoL methodology](/cex-pol-methodology) for interpretation.